The present disclosure relates to a memory device, and more particularly, to a nonvolatile memory device including antifuse memory cells.
In general, programmable memory is used in microcontroller units (MCUs), power integrated circuits (ICs), display driver ICs, complementary metal oxide semiconductor (CMOS) image sensors, etc., which are used in devices such as mobile device parts, automobile parts, etc. For such programmable memory, one-time programmable (OTP) memory is widely used. The OTP typically occupies a small area, does not require an additional process, and is programmed by electrically short-circuiting with a breakdown mechanism when a high voltage is applied to a thin gate oxide layer.
Programmable memory apparatuses such as OTP memory devices are usually programmed by breaking connections (using fuses) or creating connections (using antifuses) in a memory circuit. For example, a programmable read-only memory (PROM) includes a fuse and/or an antifuse at a memory position or a bit and is programmed by triggering one of the fuse and the antifuse. Once programming is done, it is usually irreversible. Usually, programming is carried out after memory apparatuses are manufactured, taking a particular end use or application into account.
Fuse connection is implemented by resistive fuse devices that open or break at a certain amount of high current. Antifuse connection is implemented by a thin barrier layer formed of a non-conductive material (such as silicon dioxide) between two conductive layers or terminals. When a sufficiently high voltage is applied to the terminals, silicon dioxide or such non-conductive material becomes a short circuit or a low-resistance conductive path between the two terminals.